Cryptococcus neoformans senses CO2 through the carbonic anhydrase Can2 and the adenylyl cyclase Cac1.

Gewiss Mogensen, Estelle and Janbon, Guihem and Chaloupka, James and Steegborn, Clemens and Fu, Man Shun and Moyrand, Frédérique and Klengel, Torsten and Pearson, David S. and Geeves, Michael A. and Buck, Jochen and Levin, Lonny R. and Mühlschlegel, Fritz A. (2006) Cryptococcus neoformans senses CO2 through the carbonic anhydrase Can2 and the adenylyl cyclase Cac1. Eukaryotic Cell, 5 (1). pp. 103-111. (Access to this publication is restricted)

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Abstract

Cryptococcus neoformans, a fungal pathogen of humans, causes fatal meningitis in immunocompromised patients. Its virulence is mainly determined by the elaboration of a polysaccharide capsule surrounding its cell wall. During its life, C. neoformans is confronted with and responds to dramatic variations in CO2 concentrations; one important morphological change triggered by the shift from its natural habitat (0.033% CO2) to infected hosts (5% CO2) is the induction of capsule biosynthesis. In cells, CO2 is hydrated to bicarbonate in a spontaneous reaction that is accelerated by carbonic anhydrases. Here we show that C. neoformans contains two beta-class carbonic anhydrases, Can1 and Can2. We further demonstrate that CAN2, but not CAN1, is abundantly expressed and essential for the growth of C. neoformans in its natural environment, where CO2 concentrations are limiting. Structural studies reveal that Can2 forms a homodimer in solution. Our data reveal Can2 to be the main carbonic anhydrase and suggest a physiological role for bicarbonate during C. neoformans growth. Bicarbonate directly activates the C. neoformans Cac1 adenylyl cyclase required for capsule synthesis. We show that this specific activation is optimal at physiological pH.

Item Type: Article
Subjects: Q Science
Divisions: Faculties > Science Technology and Medical Studies > School of Biosciences > Biomedical Research Group
Depositing User: Sue Davies
Date Deposited: 19 Dec 2007 17:50
Last Modified: 16 Jul 2014 11:01
Resource URI: http://kar.kent.ac.uk/id/eprint/51 (The current URI for this page, for reference purposes)
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